Gr 9 NATURAL SCIENCES: CH 3.7 What is electrical power?

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Questions and Answers

What is the energy charge per kWh for the first 50 kWh of a household's monthly energy consumption?

  • 83.32 c/kWh
  • 124.74 c/kWh
  • 137.03 c/kWh
  • 67.07 c/kWh (correct)

A household uses 350 kWh of energy in a month. Which block of the tariff structure will it fall under?

  • Block 3 (correct)
  • Block 1
  • Block 2
  • Block 4

How do you calculate the cost of using an electrical appliance?

  • price x power rating x time
  • power rating x time x price (correct)
  • time x power rating x price
  • power rating x price x time

What is the total cost of using a 1500 W microwave for 1 hour, in rands?

<p>R1.07 (B)</p> Signup and view all the answers

Why are LED lights preferred over incandescent bulbs?

<p>They are more energy-efficient (D)</p> Signup and view all the answers

What is the purpose of conducting a household energy survey?

<p>To understand your household's energy consumption (D)</p> Signup and view all the answers

What is the environmental levy per kWh for a household's monthly energy consumption?

<p>2.28 c/kWh (B)</p> Signup and view all the answers

A household uses 700 kWh of energy in a month. How much will it cost, in rands?

<p>R592.13 (C)</p> Signup and view all the answers

What is the total cost of using a 2200 W fridge for 24 hours, in rands?

<p>R37.83 (B)</p> Signup and view all the answers

How many blocks are there in the tariff structure?

<p>4 (A)</p> Signup and view all the answers

What is the unit of energy used to measure the energy consumption of an appliance?

<p>Kilowatt-hours (kWh) (A)</p> Signup and view all the answers

What is the purpose of a tiered tariff system?

<p>To charge higher rates for higher usage (A)</p> Signup and view all the answers

What is the formula to calculate energy consumption?

<p>energy = power x time (C)</p> Signup and view all the answers

What is the primary electricity supplier in South Africa?

<p>Eskom (B)</p> Signup and view all the answers

What is the unit of power used to measure the power consumption of an appliance?

<p>Watts (W) (B)</p> Signup and view all the answers

What is the meaning of 1 kWh?

<p>1 kWh is the energy used by a 1000 W appliance running for 1 hour (B)</p> Signup and view all the answers

What is the formula to calculate energy consumption in kWh?

<p>energy = power (in kW) x time (in hours) (B)</p> Signup and view all the answers

What is the purpose of VAT (Value-Added Tax)?

<p>To add a tax to the value of goods and services (C)</p> Signup and view all the answers

What is an electrical appliance?

<p>A device that uses electrical energy to perform a function (C)</p> Signup and view all the answers

What is the purpose of a survey?

<p>To gather data from respondents to gain information (A)</p> Signup and view all the answers

What is the primary function of a tiered tariff system?

<p>To encourage responsible energy consumption by increasing rates for higher usage (A)</p> Signup and view all the answers

What is the unit of measurement for power consumption of an appliance?

<p>Watts (W) (D)</p> Signup and view all the answers

Why are kilowatt-hours (kWh) used to measure energy consumption?

<p>Because they make large numbers more manageable (C)</p> Signup and view all the answers

What is the purpose of conducting a household energy survey?

<p>To gather data on energy consumption patterns (D)</p> Signup and view all the answers

What is the formula to calculate energy consumption in Joules?

<p>Energy = Power × Time (A)</p> Signup and view all the answers

What is the purpose of adding VAT (Value-Added Tax) to the cost of energy?

<p>To generate revenue for the government (B)</p> Signup and view all the answers

What is the definition of an electrical appliance?

<p>A device that uses electrical energy to perform a function (B)</p> Signup and view all the answers

What is the total energy cost in cents for a household using 450 kWh in a month?

<p>31,691.2 (C)</p> Signup and view all the answers

How does Eskom charge consumers for their energy usage?

<p>Based on a tiered tariff system (B)</p> Signup and view all the answers

A household uses a 1000 W (1 kW) electric kettle for 2 hours a day. What is the daily energy cost in cents?

<p>147.2 (B)</p> Signup and view all the answers

What is the benefit of using LED lights over incandescent bulbs?

<p>All of the above (D)</p> Signup and view all the answers

What is the purpose of measuring energy consumption?

<p>All of the above (D)</p> Signup and view all the answers

What is the energy charge in cents per kWh for the block of 351-600 kWh?

<p>124.74 (D)</p> Signup and view all the answers

What is the main purpose of conducting a household energy survey?

<p>To understand household energy consumption (A)</p> Signup and view all the answers

If a household uses 800 kWh in a month, in which block of the tariff structure will it fall?

<p>Block 4 (B)</p> Signup and view all the answers

What is the total cost in rands for a household using 600 kWh in a month?

<p>R420.12 (D)</p> Signup and view all the answers

A household uses a 2500 W (2.5 kW) air conditioner for 5 hours. What is the energy cost in cents?

<p>906.25 (C)</p> Signup and view all the answers

What is the environmental levy in cents per kWh for all blocks of the tariff structure?

<p>2.28 (D)</p> Signup and view all the answers

What is the total energy cost in cents for a household using 250 kWh in a month?

<p>21,490.5 (C)</p> Signup and view all the answers

A household uses a 500 W (0.5 kW) television for 8 hours a day. What is the daily energy cost in cents?

<p>36.18 (A)</p> Signup and view all the answers

A household uses 420 kWh of energy in a month. What is the total energy cost in cents?

<p>30,170.4 (C)</p> Signup and view all the answers

A 1200 W (1.2 kW) electric oven is used for 3 hours a day. What is the daily energy cost in cents, assuming a price of 85.60 c/kWh?

<p>3,442.4 (A)</p> Signup and view all the answers

A household wants to reduce its energy consumption. Which of the following appliances would be the best replacement for an incandescent bulb?

<p>LED bulb (A)</p> Signup and view all the answers

A household uses a 3000 W (3 kW) air conditioner for 4 hours a day. What is the daily energy cost in cents, assuming a price of 139.31 c/kWh?

<p>5,625.48 (D)</p> Signup and view all the answers

A household uses 550 kWh of energy in a month. In which block of the tariff structure will it fall?

<p>Block 3 (B)</p> Signup and view all the answers

A 2000 W (2 kW) microwave is used for 2 hours a day. What is the daily energy cost in cents, assuming a price of 83.32 c/kWh?

<p>3,599.2 (C)</p> Signup and view all the answers

A household wants to reduce its energy consumption. What would be the most effective way to do so?

<p>Using energy-efficient appliances (C)</p> Signup and view all the answers

A 1500 W (1.5 kW) electric kettle is used for 3 hours a day. What is the daily energy cost in cents, assuming a price of 67.07 c/kWh?

<p>2,512.65 (C)</p> Signup and view all the answers

A household uses 720 kWh of energy in a month. What is the total energy cost in cents?

<p>62,783.2 (C)</p> Signup and view all the answers

A 1000 W (1 kW) electric toaster is used for 2 hours a day. What is the daily energy cost in cents, assuming a price of 85.60 c/kWh?

<p>1,904 (B)</p> Signup and view all the answers

What is the primary reason why Eskom uses a tiered tariff system?

<p>To recover the costs of generating and distributing electricity (A)</p> Signup and view all the answers

What is the unit of measurement for the total amount of visible light emitted by a source?

<p>Lumens (B)</p> Signup and view all the answers

What is the purpose of adding VAT to the cost of energy?

<p>To redistribute wealth from households to the government (B)</p> Signup and view all the answers

Why is it impractical to use joules to measure monthly energy consumption?

<p>Because the numbers are too large and impractical (D)</p> Signup and view all the answers

What is the formula to calculate energy consumption in joules?

<p>Energy = Power x Time (B)</p> Signup and view all the answers

What is the purpose of conducting a household energy survey?

<p>To gather data on energy consumption patterns (B)</p> Signup and view all the answers

What is the unit of measurement for energy consumption of an appliance?

<p>Kilowatt-hours (D)</p> Signup and view all the answers

Why is 1 kWh equal to 1000 W of power used for 1 hour?

<p>Because 1 kWh is a unit of energy (D)</p> Signup and view all the answers

What is the primary function of a tiered tariff system?

<p>To recover the costs of generating and distributing electricity (B)</p> Signup and view all the answers

What is the purpose of estimating energy consumption?

<p>To calculate the cost of energy consumption (A)</p> Signup and view all the answers

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